Castilla Treasure Hunts always begin on the hour. While not every hour of the day has a hunt, many of them do. At the start of each hour, there may be a server-wide notice: [Notice] Castilla Treasure Hunt starts.

When the notice appears, you can make your way to Castilla Ruins, and run around the map to search for the treasure chest using detection skill from Install Trap stance. After 5 minutes, there will be another server-wide notice: [Notice] 5 mins before the Castilla Treasure Hunt ends.

After 10 minutes, there will be one last server-wide notice: [Notice] Castilla Treasure Hunt has ended.

While you hunt for the chest, the annoying javelin-wielding mobs will knock you down repeatedly. This is somewhat similar to Fire Isle Treasure Hunt in the last zone. When the chest has been found, there will be a server-wide notice: [Notice] <Insert Family Name> Family discovered Castilla Treasure Chest.

Once the chest has been found, you can open it with either 1 Ancient Relic or 1 Ancient Gold Relic. When the chest is opened, there will be a server-wide notice: [Notice] Someone found <Insert Item Name> in the Castilla Treasure Chest.

If there are other known drops not listed above, please post a comment on this blog entry or in the shout box. Thanks. I will update the loot list as I see more people finding the treasure in-game as well.